Anti-GBM antibody in a patient with diabetic nephropathy; all that glitters is not gold.

We present the case of a 58-year-old male diabetic patient admitted to our department for a slight decrease in kidney function, with nephrotic range proteinuria, hematuria (16,000/ml) and positive anti-glomerular basement membrane antibodies. Kidney biopsy revealed diabetic nephropathy with no evidence of crescent formation or linear immunoglobulin deposits along the basement membrane. We discuss the various clinical settings involving positive anti-glomerular basement membrane in the absence of crescentic glomerulonephritis.

Influence of a GC base pair on excitation energy transfer in DNA-assembled phenanthrene π-stacks.

The effect of a GC base pair on the excitation energy transfer in a DNA-based, light harvesting assembly of phenanthrene and pyrene chromophores is described. After absorption of light at 320 nm by the stacked phenanthrene building blocks, the excitation energy is transferred to the pyrene and leads to the formation of a phenanthrene-pyrene exciplex. The fluorescence intensity depends on the number of light absorbing phenanthrenes, as well as on the type of DNA base pair flanking the phenanthrene stack. In comparison to an AT base pair, a GC base pair located next to the stacked aromatic residues results in a reduction of fluorescence. The degree of quenching is dependent on the length of the phenanthrene stack that separates the GC base pair from the exciplex. Overall, a large number of stacked phenanthrenes positively affects exciplex fluorescence by increasing the quantity of absorbed light and, at the same time, reducing the effect of quenching by GC base pairs.

Interest of a Kidney Biopsy to Rule out ANCA-Associated Renal Vasculitis in Glomerulonephritis Patients with a Positive ANCA.

Kidney biopsy is the gold standard for diagnosing glomerular kidney disease. Some authors debate the necessity of systematically performing kidney biopsies in ANCA-associated vasculitis (AAV) to confirm the diagnosis and assess the severity of renal damage. Nevertheless, kidney involvement is considered an organ-threatening disease requiring an aggressive immunosuppressive regimen. We present a series of 4 cases with a high clinical suspicion of ANCA-associated crescentic glomerulonephritis based on rising serum creatinine, presence of proteinuria and/or hematuria, and presence of ANCA with specificity against PR-3 or MPO. The main diagnosis, however, was arterionephrosclerosis without renal AAV. Certain comorbidities, such as diabetes and/or high blood pressure, can quickly mimic progressive glomerulonephritis. In addition, some patients with AAV do not have high creatinine, proteinuria, or hematuria levels. ANCA alone is not specific to AAV and has a poor positive predictive value. The main concern is to prevent the unnecessary, inappropriate complications of heavy immunosuppression, i.e., serious infections or risk of future malignancies. Kidney pathological confirmation is important in patients with no compatible extra-renal manifestations of AAV or any other possible renal diagnosis such as may be found in polyvascular disease or diabetic patients.

Characteristics of outpatients referred for a first consultation with a nephrologist: impact of different guidelines.

INTRODUCTION: Chronic kidney disease (CKD) affects > 10% of the population but not all CKD patients require referral to a nephrologist. Various recommendations for referral to nephrologists are proposed worldwide. We examined the profile of French patients consulting a nephrologist for the first time and compared these characteristics with the recommendations of the International Kidney Disease: Improving Global Outcomes (KDIGO), the French "Haute Autorité de Santé" (HAS), and the Canadian Kidney Failure Risk Equation (KFRE). METHODS: University Hospital electronic medical records were used to study patients referred for consultation with a nephrologist for the first time from 2016 to 2018. Patient characteristics (age, sex, diabetic status, estimated glomerular filtration rate (eGFR) and urine protein-to-creatinine ratio (PCR), etiology reported by the nephrologist) and 1-year patient follow-up were analyzed and compared with the KDIGO, HAS and Canadian-KFRE recommendations for referral to a nephrologist. The stages were defined according to the KDIGO classification, based upon kidney function and proteinuria.  RESULTS: The 1,547 included patients had a median age of 71 [61-79] years with 56% males and 37% with diabetes. The main nephropathies were vascular (40%) and glomerular (20%). The KDIGO classification revealed 30%, 47%, 19%, 4% stages G1-2 to G5, and 50%, 22%, 28% stages A1-A3, respectively. According to KDIGO, HAS and KFRE scores, nephrologist referral was indicated for 42%, 57% and 80% of patients respectively, with poor agreement between recommendations. Furthermore, we observed 890 (57%) patients with an eGFR> 30 ml/min and  a urine protein to creatinine ratio 0.5 g/g, mostly aged over 65 years (67%); 40% were diabetic, and 57% had a eGFR > 45 ml/min/1.73m2, 56% were diagnosed as vascular nephropathy and 11% with unknown nephropathy. CONCLUSION: These results underline the importance of better identifying patients for referral to a nephrologist and informing general practitioners. Other referral criteria (age and etiology of the nephropathy) are debatable.

Two cases of secondary AA amyloidosis involving the skin and chronic kidney infection with a nephrotic syndrome in a high-income country.

We present two French cases of amyloid-associated (AA) amyloidosis secondary to chronic infections. Patient 1, a 51-year-old heroin addict, was hospitalised for chest pain and anasarca. During hospitalisation, a nephrotic syndrome with an inflammatory condition was discovered along with a chronic skin ulcer on his arm. Salivary gland and kidney biopsies confirmed the diagnosis of AA amyloidosis. Renal function quickly declined and haemodialysis was initiated 6 months later. Patient 2, a 55-year-old woman, was hospitalised for obstructive pyelonephritis secondary to coraliform lithiasis. Renal insufficiency with an impure nephrotic syndrome was found. After nephrectomy due to chronic pyelonephritis and an atrophic cortex on the abdominal scan, the histology revealed AA amyloidosis. Despite treatment with ACE inhibitors and control of inflammation, the nephrotic syndrome persisted with rapid decline of the kidney function.

Humanized anti CD-20 as an alternative in chronic management of relapsing thrombotic thrombocytopenic microangiopathy resistant to rituximab due to anti chimeric antibody.

Acquired Immune thrombotic thrombocytopenic purpura (iTTP) is considered among clinical situations that needs not only urgent treatment in acute setting but also long term management to prevent relapses. Important progresses have been made in management of these patients that are definitely associated with reduced mortality and relapse rate. However, there are still noticeable percentage of patients that may relapse despite application of modern treatment strategies including preemptive rituximab infusions. Hereby, we share our experience concerning a frequently relapsing iTTP due to development of anti-rituximab antibody. In our case administration of obinutuzumab, a humanized type II anti CD-20 antibody was associated with complete peripheral blood B cell depletion and increasing plasma ADAMTS-13 activity.

Physiological role of plasma and its components and the clinical implications of different methods of apheresis: A narrative review.

Nowadays, therapeutic plasmapheresis (TP) is accepted as part of the treatment for specific groups of diseases. The availability of different methods, including double filtration and adsorption, increases selectivity for the removal of substances. However, the use of these techniques requires a thorough understanding of the characteristics and components of plasma. By considering pivotal papers from several databases, the aim of this narrative review is to describe the characteristics of plasma related to apheresis techniques. We have tried to cover the clinical implications including physiology, estimation of plasma volume, viscosity, and a description of its components including the size, volume of distribution, and half-lives of the different substances to be removed or maintained depending on the clinical situation and applied apheresis technique. Applying this knowledge will help us to choose the right method and dosage and improve the efficacy of the procedure by preventing or addressing any complications.

Oligopyrenotides: abiotic, polyanionic oligomers with nucleic acid-like structural properties.

Oligopyrenotides, abiotic oligomers that exhibit significant structural analogies to the nucleic acids, are described. They are composed of achiral, phosphodiester-linked pyrene building blocks and a single chiral 1,2-diaminocyclohexane unit. These oligomers form stable hybrids in aqueous solution. Hybridization is based on stacking interactions of the pyrene building blocks. They show thermal denaturation/renaturation behavior that closely resembles DNA and RNA hybridization. In addition, oligopyrenotides display salt-concentration-dependent structural polymorphism. Thus, they possess a number of structural attributes that are typical of nucleic acids and therefore may serve as model systems for the design of artificial self-replicating systems.

Binding of Europium(III) to a non-nucleosidic phenanthroline linker in DNA.

Eu(III) complexes of DNA containing a non-nucleosidic linker, a derivative of 1,10-phenanthroline-2,6-dicarboxamide (Q), are studied with the goal of forming novel lanthanide ion binding sites that are incorporated in the backbone of DNA. One oligonucleotide is short and unstructured (TTTQTTT (QT6)) and the other (5'-AGCTCGGTCAQCGAGAGTGCA-3' (SQ)) is studied both in single-stranded form and in the presence of a partially complementary DNA strand. Luminescence spectroscopy studies show that Eu(III) binds to SQ, QT6, AQB, or QB 1100-, 56-, 23-, or 27-fold more tightly, respectively, than to a simple 1,10-phenanthroline-2,6-dicarboxamide ligand (Q1). Direct excitation and phenanthroline sensitized luminescence spectroscopy supports binding of Eu(III) to the phenanthroline linker in QT6 and in double-stranded DNA formed from SQ and partially complementary sequences that place Q in a bulge-like position. Eu(III) hydration numbers range from 3 to 5 when bound to the phenanthroline moiety in modified DNA, consistent with binding to the tetradentate linker and, in some cases, coordination to other groups in the DNA. Thermal melting experiments show that Q in a bulge-like structure stabilizes double-stranded DNA and that Eu(III) binding does not markedly affect the stability of the duplex.

Pneumocystis jirovecii pneumonitis: cause of acute hypercalcaemia in chronic haemodialysis patient.

A 76-year-old renal transplant patient due to autosomal dominant polycystic kidney disease who resumed chronic haemodialysis was admitted to our hospital for confusion and lassitude. He was afebrile and physical examination revealed diffuse bilateral rales with decreased respiratory sounds in lower right lung. Laboratory data showed hypercalcaemia (total calcium 3.92 mmol/L (normal range 2.2-2.6 mmol/L), ionised calcium 1.87 mmol/L (1.15-1.35 mmol/L)), low intact parathyroid hormone (iPTH) 15 ng/L, (15-65 ng/L) and high 1,25(OH)2D3 128.9 pg/mL, (15.2-90.1 pg/mL). Chest CT-scan revealed bilateral apical lung lesions after 15 days of antibiotics. Bronchoalveolar sample was PCR positive for Pneumocystis jirovecii He was treated with an extra session of haemodialysis with 1.25 mmol/L dialysate calcium concentration, oral trimethoprim-sulfamethoxazole was started and oral corticosteroid dose increased to 1 mg/kg for 1 week. Hypercalcaemia decreased progressively after initiation of these treatments. We concluded a case of hypercalcaemia secondary to P. jirovecii infection.

Use of double filtration plasmapheresis for the treatment of acquired thrombocytopenic thrombotic purpura.

Double filtration plasmapheresis (DFPP) could be an alternative method to simple plasma exchange plasmapheresis in the treatment of acquired thrombotic thrombocytopenic purpura (aTTP). In a retrospective single center case series, we studied clinical presentation, management care, and prognosis of aTTP patients from our academic center treated with DFPP and IV infusion of fresh frozen plasma (FFP) between 2009 and 2018. Nine patients were included for 11 episodes. Median age was 38 years old (IQR 26-53) with 78% women. Six episodes (55%) required admission to the ICU, four of which required mechanical ventilation. Median FFP volume transfused was 35.2 mL/kg/d of session. Response was complete for nine episodes (82%). Four patients presented an early relapse, two a late relapse. Four patients died: one had an active untreated HCV infection, and two were over 80-year-old polymorbid patients. DFPP seems to be an efficient method of therapeutic plasmapheresis in TTP when combined with FFP transfusion and immunosuppressive treatments.

C5b9 Deposition in Glomerular Capillaries Is Associated With Poor Kidney Allograft Survival in Antibody-Mediated Rejection.

C4d deposition in peritubular capillaries (PTC) reflects complement activation in antibody-mediated rejection (ABMR) of kidney allograft. However, its association with allograft survival is controversial. We hypothesized that capillary deposition of C5b9-indicative of complement-mediated injury-is a severity marker of ABMR. This pilot study aimed to determine the frequency, location and prognostic impact of these deposits in ABMR. We retrospectively selected patients diagnosed with ABMR in two French transplantation centers from January 2005 to December 2014 and performed C4d and C5b9 staining by immunohistochemistry. Fifty-four patients were included. Median follow-up was 52.5 (34.25-73.5) months. Thirteen patients (24%) had C5b9 deposits along glomerular capillaries (GC). Among these, seven (54%) had a global and diffuse staining pattern. Twelve of the C5b9+ patients also had deposition of C4d in GC and PTC. C4d deposits along GC and PTC were not associated with death-censored allograft survival (p = 0.42 and 0.69, respectively). However, death-censored allograft survival was significantly lower in patients with global and diffuse deposition of C5b9 in GC than those with a segmental pattern or no deposition (median survival after ABMR diagnosis, 6 months, 40.5 months and 44 months, respectively; p = 0.015). Double contour of glomerular basement membrane was diagnosed earlier after transplantation in C5b9+ ABMR than in C5b9- ABMR (median time after transplantation, 28 vs. 85 months; p = 0.058). In conclusion, we identified a new pattern of C5b9+ ABMR, associated with early onset of glomerular basement membrane duplication and poor allograft survival. Complement inhibitors might be a therapeutic option for this subgroup of patients.

Contribution of social isolation, restraint, and hindlimb unloading to changes in hemodynamic parameters and motion activity in rats.

The most accepted animal model for simulation of the physiological and morphological consequences of microgravity on the cardiovascular system is one of head-down hindlimb unloading. Experimental conditions surrounding this model include not only head-down tilting of rats, but also social and restraint stresses that have their own influences on cardiovascular system function. Here, we studied levels of spontaneous locomotor activity, blood pressure, and heart rate during 14 days under the following experimental conditions: cage control, social isolation in standard rat housing, social isolation in special cages for hindlimb unloading, horizontal attachment (restraint), and head-down hindlimb unloading. General activity and hemodynamic parameters were continuously monitored in conscious rats by telemetry. Heart rate and blood pressure were both evaluated during treadmill running to reveal cardiovascular deconditioning development as a result of unloading. The main findings of our work are that: social isolation and restraint induced persistent physical inactivity, while unloading in rats resulted in initial inactivity followed by normalization and increased locomotion after one week. Moreover, 14 days of hindlimb unloading showed significant elevation of blood pressure and slight elevation of heart rate. Hemodynamic changes in isolated and restrained rats largely reproduced the trends observed during unloading. Finally, we detected no augmentation of tachycardia during moderate exercise in rats after 14 days of unloading. Thus, we concluded that both social isolation and restraint, as an integral part of the model conditions, contribute essentially to cardiovascular reactions during head-down hindlimb unloading, compared to the little changes in the hydrostatic gradient.